Variable pressure control system for dual acting actuators

ABSTRACT

A variable pressure control system for varying pressures in the fluid circuits of a dual acting actuator over a range of pressures. The variable pressure control system includes a controller that cooperates with pressure regulators for regulating the desired pressure in the fluid circuits.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 15/049168, filedFeb. 22, 2016; which is a continuation of U.S. application Ser. No.14/047,465, filed Oct. 7, 2013, now U.S. Pat. No. 9,301,438; which is acontinuation of U.S. application Ser. No. 12/970,708, filed Dec. 16,2010, now U.S. Pat. No. 8,550,020.

BACKGROUND

Most control systems for dual acting hydraulic or pneumatic cylinders oractuators utilize a directional control valve for controlling the flowof fluid under a constant or predefined pressure to force the actuatorrod to extend or retract. In some applications, it would be desirable tonot only control the direction of the fluid flow for actuating anactuator, but also to vary or regulate the fluid pressure in the fluidcircuits for actuating the actuators.

One application in particular where it would be desirable to control theactuators as well as regulate or vary the fluid pressure in the fluidcircuits is in connection with row cleaners on an agricultural planter.Row cleaners, such as disclosed in U.S. Pat. No. 7,673,570 (“the '570patent”), incorporated herein in its entirety by reference, are used toclear away crop residue, soil clods and other debris that can interferewith proper furrow formation and seed growth. When planting fields withheavy crop residue, it may be desirable to exert extra downforce on therow cleaner to ensure a more aggressive action of the row cleaner toclear away the heavy crop residue. In field conditions where the cropresidue is light, a less aggressive action of the row cleaner may bedesired. To increase or decrease the aggressiveness of the row cleanerwhile on-the-go during planting operations, a hydraulic or pneumaticcylinder is typically employed to raise and lower the row cleaner. Inconventional control systems for raising and lowering row cleanersequipped with a hydraulic or pneumatic actuators, the operator's onlycontrol over the row cleaners is through movement of a lever fore or aftto open and close a directional control valve in the fluid circuitthereby causing the row cleaner actuator to extend or retract torespectively lower or raise the row cleaner. Accordingly, as the plantertraverses the field, the operator is required to continually look backat the row cleaners and adjust their height up or down to maintain thedesired amount of aggressiveness as the soil conditions, terrain andamount of crop residue vary.

The control system disclosed in the '570 patent allows the operator toset a desired downpressure for the row cleaner which is thenautomatically maintained as the planter traverses the field. The '570patent also allows the operator to change the pressure of the hydraulicfluid supplied to the cylinders. However, the pressure in the fluidcircuits is controlled through an electronic control system incombination with an accumulator having a hydraulic fluid chamber and apressurized gas chamber. Thus, while the control system of the '570patent may serve its intended purpose it is a complex system with ahigher associated cost.

It is desirable, therefore, to provide a control system which allows anoperator to set a desired pressure in the fluid circuits so that as soilconditions and terrain vary during planting operations as the plantertraverses the field, the actuator will self adjust to maintain thedesired preset pressure in the fluid circuits. By maintaining thedesired preset pressure in the fluid circuits, the row cleaner willfollow the terrain or contours of the field while maintaining thedesired amount of aggressiveness of the row cleaner. Furthermore, itwould be desirable for such a control system to be relatively low incost and simple to install and which is simple and intuitive to operatewithout the need for electronics and microprocessors.

Such a control system may have applications to other ground engagingdevices on agricultural equipment or wherever there is a need for a lowcost, simple and intuitive control system for providing directionalcontrol of hydraulic or pneumatic actuators over a range of variablepressures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a preferred embodiment of acontrol system for controlling fluid flow for actuation of one or moredual acting actuators.

FIG. 2A is a front perspective view of a preferred embodiment of acontroller for the control system of FIG. 1.

FIG. 2B is a rear perspective view of the controller of FIG. 2A.

FIG. 3A is a perspective view of a preferred embodiment of a regulatorassembly for the control system of FIG. 1.

FIG. 3B is another perspective view of the regulator assembly of FIG.3A.

FIG. 3C is another perspective view of the regulator assembly of FIG.3A.

FIG. 4 is a cross-sectional view of the regulator assembly as viewedalong lines 4-4 of FIG. 3A.

FIG. 5 is an exploded perspective view of a pressure regulating valvefor the control system of FIG. 1.

FIG. 6 is a schematic illustration of the first and second fluidcircuits of the control system of FIG. 1.

FIG. 7A is a perspective view of a preferred embodiment of a piston forthe regulator assembly of FIG. 3A.

FIG. 7B is a top plan view of the piston of FIG. 7A.

FIG. 8A is a perspective view of a preferred embodiment of a cam shaftfor the regulator assembly of FIG. 3A.

FIG. 8B is another perspective view of the cam shaft of FIG. 8A.

FIG. 8C is a side elevation view of the cam shaft of FIG. 8A.

FIG. 8D is another perspective view of the cam shaft of FIG. 8A.

FIG. 8E is an end elevation view the cam shaft of FIG. 8A.

FIG. 9 graphically illustrates the relationship of the fluid pressuresin the down circuit and lift circuit versus the angular position of theuser interface of the controller of FIG. 2A.

FIG. 10 is a partial side elevation view of a row unit of anagricultural planter showing a row cleaner incorporating the controlsystem of FIG. 1.

FIG. 11 is a perspective view of the row cleaner of FIG. 10incorporating the control system of FIG. 1.

FIG. 12 illustrates an alternative embodiment of a regulator biasingmechanism for the controller.

DESCRIPTION

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views, FIG. 1schematically illustrates a control system 100 for controlling actuationof one or more dual acting actuators 200, such as pneumatic or hydrauliccylinders. The control system 100 includes a controller 300 and apressure source 600, which provides a substantially constant pressure tothe controller 300. Conduits 500 fluidly connect the pressure source600, the controller 300 and the actuators 200. The controller 300incorporates a pressure regulator assembly 400 which permits theoperator to vary or regulate the pressure applied to actuate theactuators 200.

As discussed later, the control system 100 is particularly adapted foruse with an agricultural planter 10 (FIG. 10) for controlling rowcleaners 12 or other soil engaging members. However, those skilled inthe art will appreciate that the control system 100 may have otherequally suitable uses wherever it is desirable to provide a simple andintuitive means for directional control of hydraulic or pneumaticactuators over a range of variable fluid pressures.

It should also be appreciated that although the preferred embodiment ofthe control system 100 as described herein is a pneumatic system, thoseskilled in the art would understand the control system 100 could beadapted to a hydraulic system. Accordingly, the term “fluid” should beunderstood to include or refer to any fluid medium, including air,hydraulic oil or any other suitable fluid. Additionally, although theterm “air” may be used when referring to the fluid used in the preferredembodiment or when describing a feature of the preferred embodiment, itshould be understood that if the system 100 is adapted to a hydraulicsystem, any reference to air flow would of course be replaced withhydraulic oil or other fluid medium.

Referring to FIGS. 2A and 2B, the controller 300 includes a pressureregulator assembly 400 (FIG. 2B). The pressure regulator assembly 400 ishoused within the housing 302 of the controller. A user interface 304 isprovided for interfacing with the pressure regulator assembly 400 and ispreferably configured to be easily grasped by the hand of an operatorsuch as a lever, a dial or the like. The controller 300 also preferablyincludes visual indicators that display the source pressure 306, thelift pressure 308 and the down pressure 310. The down pressure 310 isthe amount of pressure on the side of the fluid circuit for extendingthe actuator ram 202 (hereinafter the “down circuit”). The lift pressure308 is the amount of pressure on the side of the circuit for retractingthe actuator ram 202 (hereinafter the “lift circuit”). The visualindicators 306, 308, 310 may be analog gauges or digital displays, orany other desired visual indicator of pressure in the respective fluidcircuits.

By moving the user interface 304 (hereinafter the “lever 304”), theoperator is preferably able to set the desired amount of fluid pressurein the down circuit and lift circuit by rotating the lever 304 clockwiseor counter-clockwise as viewed in FIG. 2A. The further the operatorrotates the lever 304 counterclockwise or in the direction labeled“LIFT”, the greater the pressure in the lift circuit. Likewise, thefurther the operator rotates the lever 304 clockwise or in the directionlabeled “DOWN,” the greater the pressure in the down circuit. Asdepicted in the embodiment of the controller 300 of FIG. 2A, thepressure in the down circuits and lift circuits is variable over a rangefrom 0 psi when the lever 304 is in the vertical position to 120 psiwhen the handle is rotated 90 degrees counterclockwise or 90 degreesclockwise. FIG. 9 graphically illustrates how the pressure increasesdepending on the angular position of the lever 304 in either directionfrom the vertical neutral position at which point the pressure is zeroand/or substantially equal or constant in both the down circuits andlift circuits. Of course, it should be appreciated that the pressureranges, the user interface 304, the visual indicators 306, 308, 310 andother features of the controller 300 described above may be altered orvaried depending on preferences and the particular application of thecontrol system 100. As such, the controller 300 should not be construedas being limited to the particular embodiment described and illustratedherein.

A preferred embodiment of the pressure regulator assembly 400 isillustrated in FIGS. 3A-3C. FIG. 4 shows a cross-section of thepreferred assembly 400 as viewed along lines 4-4 of FIG. 3A. Thepressure regulator assembly 400 includes a main body 402, a firstregulator 404, a second regulator 406 and a regulator biasing mechanism408. The regulator biasing mechanism 408 is moveable within the mainbody 402 and cooperates with the first and second regulators 404, 406for controlling the flow of air or other fluid therethrough as describedin detail later. The regulator biasing mechanism 408 is operablyconnected to the user interface 304, via a camshaft 470 (discussedlater) such that movement of the user interface 304 results in acorresponding movement of the regulator biasing mechanism 408 within themain body 402.

FIG. 5 is an exploded perspective view of the preferred first and secondregulators 404, 406. The first and second regulators 404, 406 arepreferably ported regulators such as those manufactured by Norgren,Inc., model no. R07-100-RNLA, although other regulators having differentconfigurations may be equally suitable. Each of the regulators 404, 406comprises a regulator housing 410 defining an inlet port 412, an outletport 414 and a valve seat 416. The inlet and outlet ports 412, 414 arepreferably disposed at 90 degree angles from one another. A pressureregulating valve 420 is positioned within the valve seat 416 to controlair flow from the inlet port 412 to the outlet port 414. For clarity theinlet and outlet ports of the first regulator 404 are hereinafterreferred to using reference characters 412-1 and 414-1, respectively.Likewise, the inlet and outlet ports of the second regulator 406 arehereinafter referred to using reference characters 412-2 and 414-2,respectively.

FIG. 6 schematically illustrates the preferred lift circuits and downcircuits of the control system 100 for controlling the dual actingactuator 200. The pressure supply 600 is in fluid communication with thetank pressure visual indicator 306 and the fluid inlet ports 412 of boththe first and second regulators 404, 406. The pressure regulating valve420 regulates the fluid flow based on the position of the regulatorbiasing mechanism 408 controlled by the lever 304. The first regulatoroutlet port 414-1 is in fluid communication with the lift circuit andvisual indicator 308. The second regulator outlet port 414-2 is in fluidcommunication with the down circuit and visual indicator 310.

Referring again to FIG. 4 in conjunction with FIG. 5, the pressureregulating valve 420 of the first and second regulators 404, 406includes a diaphragm 422 and a valve body 424. The valve body 424 has acylindrical shaft 425, an outer flange 426, an axial opening 432 andaxial fluid passageways 433. The cylindrical shaft 425 of the valve body426 is received within an o-ring 428. The o-ring 428 is seated in theend of the valve seat 416. The outer flange 426 rests on top of theo-ring 428. The diaphragm stem 430 extends through the axial opening 432in the valve body 424. The valve spring 434 is received within the valveseat 416 and biases the plug 436 against the bottom end of the valvebody 424.

The regulators 404, 406 are preferably coaxially mounted to the ends ofthe main body 402 by a threaded connection. As the regulators arethreaded into the ends of the main body 402, a slip ring 438 and theperipheral edge of the diaphragm 422 are sandwiched between the end ofthe regulator housing 410 and an inside lip 440 of the main body 402thereby creating a fluid tight seal.

Continuing to refer to FIG. 4, the main body 402 of the regulatorassembly 400 includes an axial through-bore 450. First and second sleevebearings 452, 454 are preferably press fit into the through-bore 450.First and second pistons 456, 458 are slidably received within thesleeve bearings 452, 454, respectively. Each piston 456, 458 includes anaxial partial-bore 460 at one end. As best illustrated in FIG. 7, theother end of each piston 456, 458 includes an arcuate face 462 (FIG. 7B)and a notch 464. Seated within each partial-bore 460 of the first andsecond pistons are first and second piston springs 466, 468. The otherend of each of the first and second springs 466, 468 abuts thediaphragms 422 of the first and second regulators 404, 406 respectively.

Continuing to refer to FIG. 4 in conjunction with FIGS. 8A-8E, acamshaft 470 extends transversely through and is rotatably supported bythe main body 402. One end 476 of the camshaft 470 is preferably adaptedfor securing the lever 304 or other suitable user interface thereto. Theother end of the camshaft 470 is preferably rotateably secured to themain body 402 by threading a nut 472 onto the threaded end of thecamshaft 470. Washers 471, 473 are preferably disposed between the nut472 and the exterior of the main body 402. At least one of the washers471, 473 is preferably made of leather or other suitable material havinga relatively high coefficient of friction such that when the nut 472 issufficiently tightened against the washers, some frictional resistanceagainst unwanted rotation of the lever 304 and camshaft 470 is achievedwhile still allowing the camshaft 470 to easily rotate. This frictionalresistance allows the lever 304 to be moved to a desired position whereit will remain in place until it is again grasped by the operator andmoved to a new desired position.

The camshaft 470 further includes a stop plate 474 and first and secondoffset cams 480, 482. As best illustrated in FIG. 8E, each cam 480, 482has a lobe 484 extending radially from the axis of the camshaft 470. Thelobes 484 of each cam 480, 482 are preferably angularly offset from oneanother by an angle W, which, in the preferred embodiment, is 38.6degrees. The camshaft 470 further includes a guide disk 486. As bestillustrated in FIG. 4, the guide disk 486 is received within the notch464 of the first and second pistons 456, 458, to keep the pistons fromrotating within the through-bore 450 of the main body 402.

It should be appreciated that the first and second piston springs 466,468 bias the first and second pistons 456, 458 axially inward toward thecamshaft 470. As the operator rotates the camshaft 470 by moving thelever or other user interface 304 from side-to-side, the lobes 484 ofthe first and second offset cams 480, 482 respectively rotate againstthe arcuate contact surfaces 462 of the first and second pistons 456,458 forcing the pistons to move in the direction toward the respectiveregulators. The stop plate 474 on the camshaft 470 is oriented withrespect to the cams 480, 482 such that the first and second edges 486,488 of the stop plate 474 abut the stop screw 490 before the cams rotatebeyond the center axis of the first and second pistons 456, 458.

As previously described, in the preferred embodiment, the lever 304 isoriented in the vertical direction as shown in FIG. 2 when the camshaft470 is in the neutral position. In the vertical neutral position, thecams 480, 482 do not displace the pistons 456, 458 and the pressureregulating valves 420 are closed such that no fluid flows through thefirst or second outlet ports 414-1 or 414-2, respectively and thereforethe pressures in the down and lift circuits are substantially equal orconstant. If the operator rotates the lever 304 clockwise as shown inFIG. 2A or to the left as viewed with respect to FIG. 4, the camshaft470 to which the lever 304 is attached will likewise rotate clockwisecausing the first cam 480 to rotate toward the first piston 456. As thelobe 484 of the first cam 480 comes into contact with the arcuate face462 of the first piston 456, the first piston is forced axially leftwardtoward the first regulator 404. The pressure regulating valve 420remains closed until the axial position of the first piston 456compresses the piston spring 466 enough to create a force sufficient toovercome any opposing bias of the valve spring 432 and resistance of thediaphragm 422, at which point the diaphragm 422 will deflect to theleft. When the diaphragm is deflected, the diaphragm stem 430 forces thevalve plug 434 leftward, opening the axial passageways 433 (FIG. 5)through the valve body 424 thereby allowing pressurized air from thepressure source 600 to flow through the valve body 424, into the cavity491 (FIG. 4) and out through the first regulator outlet port 414-1.Continued rotation of the lever 304 and camshaft 470 will cause thefirst piston 456 to continue to move axially to the left resulting in anincrease in pressure in the down circuit as displayed on the “DOWN”visual indicator 310. When the pressure in the down circuit increasessufficiently such that the pressure in the cavity 491 on the backside ofthe diaphragm 422 overcomes the biasing force of the piston spring 466,the diaphragm 422 will return to its neutral or non-deflected state. Thepressure in the down circuit will remain at this pressure until thelever 304 is moved further to the left or until the lever 304 isreturned to the neutral position.

During planting operations, the operator will rotate the lever 304 to adesired down pressure position as indicated on the visual indicator 310to achieve the desired aggressiveness of the row cleaner. If soilconditions change causing the row cleaner to pivot upwardly, thepressure in the down circuit will suddenly increase as the piston rod isforced inwardly. If the increase in pressure in the cavity 491 acting onthe backside of the diaphragm 422 exceeds the bias of the piston spring466, the diaphragm will deflect to the right. As the diaphragm 422 anddiaphragm stem 430 move to the right, the passageways 433 through thevalve body 424 will be opened as the diaphragm stem 430 lifts off thevalve plug 436 thereby permitting air to bleed off by passing throughthe axial passageway 492 extending through the diaphragm stem 430 anddiaphragm 422. The air will then pass into the through-bore 450 which isopen to atmosphere by apertures 494 through the main body 402. The airwill continue to bleed off until the pressure on the backside of thediaphragm 422 in the cavity 491 is less than the bias of the pistonspring 466 such that the diaphragm returns to its neutral ornon-deflected state. With the diaphragm 422 in the neutral ornon-deflected state, the passageways 433 are again closed off as thevalve plug 436 abuts the end of the diaphragm stem 430. The same actionwill occur if the operator rotates the lever 304 back to the center orneutral position from a down position.

Likewise if the soil conditions change causing the row cleaner to pivotdownwardly, the pressure in the down circuit will suddenly decrease asthe piston rod extends due to the loss of upward force exerted by thesoil. If the pressure in the cavity 491 acting on the backside of thediaphragm 422 is less than the bias of the piston spring 466, thediaphragm will deflect to the left. As the diaphragm 422 and diaphragmstem 430 move to the left, the passageways 433 through the valve body424 will be opened thereby allowing pressurized air from the pressuresource 600 to flow through the valve body 424, into the cavity 491 andout through the first regulator outlet port 414-1. When the pressure inthe down circuit increases sufficiently such that the pressure in thecavity 491 on the backside of the diaphragm 422 overcomes the biasingforce of the piston spring 466, the diaphragm 422 will return to itsneutral or non-deflected state.

Thus, it should be appreciated that the desired preset pressure in thedown circuit as set by the position of lever 304 will be maintained bythe pressure regulating valve opening and closing as necessary as soilelevations or other soil conditions change, thereby maintaining thedesired amount of aggressiveness of the row cleaner with the soil.

It should be appreciated that because the second cam 482 is sufficientlyoffset from the first cam 480, the second regulator 406 remains closedand no fluid flows through the second regulator outlet port 414-2throughout the full range of clockwise rotation of the lever 304 andleftward deflection of the first piston 456. As such, the pressure inthe lift circuit remains substantially constant. It should also beappreciated that rotating the lever 304 counterclockwise as viewed inFIG. 2A or to the right as viewed in FIG. 4 will result in the same butopposite movement of the second piston 458 and corresponding movement ofthe components of the second regulator 406 to permit fluid flow throughthe second regulator outlet 414-2. Likewise, the first regulator 404remains closed such that no fluid flows through the first regulatoroutlet port 414-1 throughout the full range of counterclockwise rotationof the lever 304 and rightward deflection of the second piston 456. Assuch, the pressure in the down circuit remains substantially constant.This relationship is graphically represented in FIG. 9 which illustratesthat the pressures at the outlet ports 414-1 and 414-2 of the first andsecond regulators 404, 406 is a function of the angle of rotation of thelever 304 with respect to the neutral position, designated as 0 on thex-axis. Thus, when the lever 304 is rotated clockwise as viewed in FIG.2A, the pressure at the outlet port 414-1 of the first regulator 404increases proportionally until the maximum pressure is achieved when thelever is at +90 degrees, while the pressure at the outlet port 414-2 ofthe second regulator 406 remains at zero. Conversely, when the lever 304is rotated counterclockwise as viewed in FIG. 2A, the pressure at theoutlet port 414-2 of the second regulator 406 increases proportionallyuntil the maximum pressure is achieved when the lever is at −90 degrees,while the pressure at the outlet port 414-1 of the first regulator 404remains at zero.

It should be appreciated that with changes in the configuration andshape of the camshaft 470, the pressure characteristics illustrated inFIG. 9 may be varied. For example, the curves may be shifted apart suchthat both pressures are zero for lever positions within, e.g., 5 degreesof the neutral position. Similarly, the curves may be shifted togethersuch that neither pressure is zero at the same time. The range ofrotation required to obtain maximum pressure at each outlet port 414 mayalso be varied, and may be substantially symmetrical (as illustrated inFIG. 9) or may be asymmetrical such that a lesser range of rotation isrequired to obtain full pressure at, e.g., outlet port 414-1 than 414-2.

In all orientations of the lever 304, the visual indicators 306, 308,310 are configured to display the pressure at the pressure supply 600,in the down circuit at the first regulator outlet 414-1, and in the liftcircuit at the second regulator outlet 414-2 respectively. And, asdisplayed in FIG. 2, it is preferred that the controller 300 is orientedsuch that when the operator turns or rotates the user interface 304clockwise, the pressure in the down circuit increases. Likewise, whenthe operator turns or rotates the user interface 304 counterclockwise,the pressure in the lift circuit increases. In this manner, the controlsystem 100 is intuitive to the operator.

Referring now to FIGS. 10 and 11, the control system 100 is illustratedin connection with a row cleaner 12 attached to a row unit 10 of anagricultural planter. Row units 10 such as described in U.S. Patent No.4,009,668, incorporated herein in its entirety by reference, are wellknown in the art. Similarly, row cleaners 12 such as disclosed in U.S.Pat. No. 7,673,570 previously incorporated herein by reference, are wellknown in the art. The row cleaner 12 includes forwardly extendingpivotal arms 14 to which ground engaging row cleaner wheels 16 arerotatably secured. The rearward ends of the row cleaner arms 14 aremounted to the row unit shank 20 by pins 22 forwardly of the furrowopening assembly 30 such that the arms 14 are free to pivot upwardly anddownwardly relative to the soil surface. The row cleaner wheels 16engage the soil surface and as the planter is drawn forwardly throughthe field as indicated by arrow 32, the row cleaner wheels 16 rotate. Asthe wheels 16 rotate through the soil, their angled orientation withrespect to the forward direction of the planter throws the debris toeither side leaving a strip of soil substantially clear of debris infront of the furrow opening assembly 30.

A bracket 710 is mounted to the row unit shank 20 by bolts or othersuitable fastening means. The bracket 710 includes forwardly projectingears 712. A pin 714 pivotally secures one end of the actuator 200 to theears 712. The other end of the actuator 200 is pivotally secured to aplate 716 mounted to the forwardly extending row cleaner arms 14. Airhoses or conduits 500 fluidly connect the actuator 200 to the controller300 and to the respective first and second regulator outlet ports 414-1,414-2 as previously described. The controller 300 (not shown in FIGS. 10and 11) is preferably mounted within the cab of the tractor forcontrolling and viewing by the operator. The pressure source 600 (notshown in FIGS. 10 and 11) is preferably mounted to the planter frame. Apreferred pressure source 600 suitable for controlling row cleaners on aplanter as hereinafter described is a 2 gallon, 12 volt air compressor,such as the air compressor available from VIAIR, model no. 350 c, inIrvine Calif.

It should be appreciated that the mass of the row cleaner 12 alone willimpose a downward force on the soil surface as the planter traverses thefield. However, by incorporating the control system 100 as describedabove, the operator is able to increase the downward force by rotatingthe lever 304 counterclockwise in the direction of the visual indicator310 preferably labeled “DOWN” as shown in FIG. 2A. As previouslydescribed, rotating the lever 304 will result in an increase in thefluid pressure in the down circuit forcing the actuator rod 202 (FIG. 6)to extend forcing the row cleaner to pivot downwardly into furtherengagement with the soil causing more aggressive action of the rowcleaner wheels 16. Likewise, to lift the row cleaners 12 so that the rowcleaner wheels 16 are raised above the soil surface (for example whenturning the planter at the headlands) or when less aggressive action ofthe row cleaner wheels is desired (for example when debris is light orother changes in soil conditions) the operator may rotate the lever 304clockwise in the direction of the visual indicator 308 preferablylabeled “LIFT” as shown in FIG. 2A. To fully lift the row cleaner 12 sothat the row cleaner wheels 16 are raised above the soil surface, thelever 304 is turned clockwise far enough to the “LIFT” side to providesufficient pressure in the lift circuit such that the actuator rod 202(FIG. 6) retracts far enough to rotate the row unit arms 14 about thepin 22 until the row cleaner wheels 16 are above the soil surface.

As illustrated in FIG. 1, the controller 300 may control multipleactuators 200 and thus multiple row cleaners 12. Alternatively, multiplecontrollers 300 may be employed to control individual actuators and rowunits or groups of actuators and row units.

In addition, it should be appreciated that other implementations may bemade of the control system 100 as described herein. For example, thecontrol system 100 may be used to vary the downforce on other groundengaging components of a planter, such as a row unit downforce system asdisclosed in U.S. Pat. No. 6,389,999 or Applicant's co-pendingapplication Ser. No. 12/679,710 (Pub. No. 2010/0198529), both of whichare incorporated herein in their entireties by reference, to vary thedownforce imposed on a row unit of the planter by an actuator such ascylinders or air bags. The control system 100 may be adapted to providevariable pressure to the down and lift circuits associated with suchdownforce actuators, enabling a user to control the downforce on the rowunit. As discussed above with respect to the row cleaners 12, thecontrol device may be adapted to simultaneously control the downforce onall of the row units. Alternatively, multiple control devices may beadapted to control sections or individual row units of the planter.

Similarly, in a planter such as that disclosed in U.S. Pat. No.4,009,668, previously incorporated by reference above, the downforce onthe closing wheels of the row unit are typically varied by an actuatorsuch as a spring (indicated by reference numeral 59 in the '668 patent).In one implementation, the actuator associated with each closing unitmay be the actuator 200. The pressures associated with the actuator 200may be controlled by the control system 100 as disclosed herein. Thus,the user is able to vary the downforce on the closing wheels of the rowunit from the cab. As discussed above with respect to the downforceactuator, such a system may be adapted to control all of the closingwheels across the entire planter or individual closing wheels or groupsof closing wheels.

Those skilled in the art will also appreciate that variousconfigurations of the camshaft 470 and the lobes 484 and theorientations of the cams 480, 482 may be suitable. Additionally, ratherthan cams, the camshaft 470 may utilize a worm gear or other suitablecooperating arrangements to convert rotation of the camshaft into linearor axial movement of the pistons.

Moreover, in other embodiments, the cams 480, 482 may be modified suchthat a constant force is applied to one of the piston springs 466, 468while the force on the other piston spring is varied. In suchembodiments, as the user varies the pressure at one circuit output, thepressure at the other circuit output remains at a constant non-zerovalue.

In still other embodiments, the cams 480, 482 may be modified such thata varying force is applied to one piston spring 466, 468 while the forceon the other piston spring is varied. For example, the cams 480, 482could be configured such that as the user moves the lever 304 from afirst orientation to a second orientation, the pressure in the firstcircuit steadily increases and the pressure in the second circuitsteadily decreases.

Moreover, further embodiments of the regulator assembly 400 may be madeto control the fluid pressures in more than two circuits. For example, asecond main body 402 may be provided with a second set of pistons may beprovided with a longer camshaft 470 incorporating a second set of camsextending through both main bodies. Thus, as the operator turns thelever 304, multiple regulators may be opened or closed to control fluidflow through multiple circuits.

In still other embodiments, the controller 400 may be modified toprovide an alternative regulator biasing mechanism 408 such thatcamshaft 470 is replaced with other devices configured to alternatelydisplace the pistons 456, 458 upon rotation of the lever 304. Forexample, as illustrated in FIG. 12 the regulator biasing mechanism 408may comprise a rack and pinion arrangement. In this embodiment, the rack802 is slidably mounted within the main body 402 such that it isconstrained to rotate in a leftward or rightward direction from theperspective shown in FIG. 12. The pinion 804 is mounted to the lever 304such that when the operator turns the lever 304 the rack 802 contactsone of the pistons 456, 458. The dimensions and gearing of the rack andpinion are preferably such that a user can move one of the pistons 456,458 through the desired range of motion, thus providing the desiredrange of pressures at the associated outlet ports 414-1, 414-2 of thefirst and second regulators 404, 406, respectively, while the otherpiston remains unmoved.

The foregoing description is presented to enable one of ordinary skillin the art to make and use the invention and is provided in the contextof a patent application and its requirements. Various modifications tothe preferred embodiment of the apparatus, and the general principlesand features of the system and methods described herein will be readilyapparent to those of skill in the art. Thus, the present invention isnot to be limited to the embodiments of the apparatus, system andmethods described above and illustrated in the drawing figures, but isto be accorded the widest scope consistent with the spirit and scope ofthe appended claims.

1. A row cleaner downforce control system, comprising: a row cleanerhaving a frame and at least one wheel, said at least one wheel disposedto rollingly contact a soil surface when traveling along a path oftravel, said at least one wheel angled with respect to said path oftravel such that said at least one wheel throws debris on said soilsurface to a side of said path of travel; a dual acting actuatoroperably coupled to said row cleaner and a pressure source, said dualacting actuator having a down chamber and a lift chamber; and acontroller in communication with said pressure source, said lift chamberand said down chamber and operable to control a down pressure in saiddown chamber and a lift pressure in said lift chamber from said pressuresource; whereby increasing said down pressure in said down chamberincreases a downforce applied by said at least one wheel on said soilsurface, and whereby increasing said lift pressure in said lift chamberdecreases said downforce applied by said at least one wheel on said soilsurface.
 2. The row cleaner downforce control system of claim 1, whereinsaid at least one wheel comprises a first wheel and a second wheel. 3.The row cleaner downforce control system of claim 1, wherein saidcontroller comprises a pressure regulating valve that selectivelymaintains said down pressure in said down chamber at any of a continuousrange of pressures.
 4. The row cleaner downforce control system of claim1, wherein said controller is configured to selectively maintain saidlift pressure in said lift chamber.
 5. The row cleaner downforce controlsystem of claim 1, further comprising: a user interface configured tomodify an operating state of said controller, whereby when a usermodifies a position of said user interface, one of said down pressureand said lift pressure is modified so as to modify said downforce. 6.The row cleaner downforce control system of claim 5, wherein said userinterface is configured to move through a continuous range of motion. 7.The row cleaner downforce control system of claim 6, wherein said rangeof motion includes a lift range and a down range, wherein said liftpressure varies according to said position of said user interface withinsaid lift range, and wherein said down pressure varies proportionallywith said position of said user interface within said down range.
 8. Therow cleaner downforce control system of claim 7, wherein said range ofmotion includes a neutral position, wherein said neutral position isdisposed between said lift range and said down range, and wherein saidlift pressure and said down pressure are equal when said user interfaceis in said neutral position.
 9. The row unit downforce control system ofclaim 1, wherein said controller comprises a lift regulator and a downregulator, wherein said lift regulator is in fluid communication withsaid lift chamber and wherein said down regulator is in fluidcommunication with said down chamber.
 10. The row unit downforce controlsystem of claim 9, wherein said user interface is configured to movethrough a continuous range of motion.
 11. The row unit downforce controlsystem of claim 10, wherein said range of motion includes a lift rangeand a down range, wherein a lift outlet pressure of said lift regulatorvaries according to said position of said user interface within saidlift range, and wherein a down outlet pressure of said down regulatorvaries proportionally with said position of said user interface withinsaid down range.
 12. The row unit downforce control system of claim 11,wherein said range of motion includes a neutral position, wherein saidneutral position is disposed between said lift range and said downrange, and wherein said lift pressure and said down pressure are equalwhen said user interface is in said neutral position.
 13. The row unitdownforce control system of claim 1, wherein said controller isconfigured to selectively maintain said lift pressure at one of a firstrange of pressures, and wherein said controller is configured toselectively maintain said down pressure at one of a second range ofpressures.
 14. The row cleaner downforce control system of claim 13,wherein said controller comprises a pressure regulating valve thatselectively maintains said down pressure in said down chamber at any ofa continuous range of pressures.
 15. The row unit downforce controlsystem of claim 2, further including a planter row unit, said planterrow unit including a furrow opening assembly, said furrow openingassembly configured to open a furrow, wherein said row cleaner ispivotally mounted to said row unit, wherein said path of travel of saidrow cleaner is parallel to said furrow, and wherein said row cleaner isdisposed in front of said furrow opening assembly with respect to saidpath of travel.